This invention relates to a tape drive such as a linear tape storage system represented by DLT (digital liner tape) or LTO (linear tape open) and, in particular, to a head protection mechanism for protecting a magnetic head in the tape drive.
Linear tape storage systems of the type described are developed as xe2x80x9cback-upxe2x80x9d systems for hard disks of computer systems and various types of the linear tape storage systems have been proposed in prior art. For example, a digital linear tape drive serving as the DLT is disclosed in U.S. Pat. No. 5,862,014 to Nute, entitled: xe2x80x9cMulti-Channel Magnetic Tape Head Module Including Flex Circuitxe2x80x9d or the like.
The digital linear tape drive (which may be merely called xe2x80x9cdriving apparatusxe2x80x9d, xe2x80x9ctape drivexe2x80x9d, or xe2x80x9cdrivexe2x80x9d) is for receiving a tape cartridge (which may be merely called xe2x80x9ccartridgexe2x80x9d) having a single reel (a supply reel) and contains a take-up reel therein. When the tape cartridge is installed in the driving apparatus, a magnetic tape is pulled out of the tape cartridge and then is wound by the take-up reel through a head guide assembly (HGA). The head guide assembly is for guiding the magnetic tape (which may be merely called xe2x80x9ctapexe2x80x9d) pulled out of the tape cartridge in a magnetic head. The magnetic head exchanges information between the tape and the magnetic head. The head guide assembly generally comprises a boomerang-shaped aluminum plate and six large guide rollers each using a bearing.
In addition, the head guide assembly is also called a tape guide assembly which is disclosed, for example, in U.S. Pat. No. 5,414,585 to Saliba, entitled: xe2x80x9cRotating Tape Edge Guide.xe2x80x9d In addition, an example of the guide roller is disclosed in Japanese Unexamined Patent Publication Tokkai No. 2000-100025 (JP 2000-100025 A).
The tape drive is generally comprised of a rectangular housing that has a common base as described, for example, in U.S. Pat. No. 5,793,574, entitled: xe2x80x9cTape Head Actuator Assembly Having A Shock Suppression Sleevexe2x80x9d to Cranson et al. The base has two spindle motors (reel motors). The first spindle motor has a spool (or a take-up reel) permanently mounted on the base and the spool is dimensioned to accept a relatively high speed streaming magnetic tape. The second spindle motor (reel motor) is adapted to accept a removable tape cartridge. The removable tape cartridge is manually or automatically inserted into the drive via a slot formed on the drive""s housing. Upon insertion of the tape cartridge into the slot, the cartridge engages the second spindle motor (reel motor). Prior to rotation of the first and the second spindle motors, the tape cartridge is connected to the permanently mounted spool (the take-up reel) by means of a mechanical buckling mechanism. A number of rollers (guide rollers) positioned intermediate the tape cartridge and the permanent spool guide the magnetic tape as it traverses at relatively high speeds back and forth between the tape cartridge and the permanently mounted spool.
In the digital linear tape drive having such a structure, an apparatus for pulling the tape from the supply reel to the take-up reel is required. Such as a pulling apparatus is disclosed, for example, in International Publication Number WO 86/07471. According to WO 86/07471, take up leader means (a first tape leader) is coupled to the take-up reel while supply tape leader means (a second tape leader) is connected to the tape on the supply reel. The first tape leader has one end formed into a mushroom like tab. The second tape leader has a locking aperture. The tab is engaged into the locking aperture.
Furthermore, a mechanism for joining the first tape leader with the second tape leader is required. Such a joining mechanism is disclosed, for example, in International Publication number WO 86/07295.
In addition, Japanese Unexamined Patent Publication Tokkai No. 2000-100116 (JP 2000-100116 A) discloses a structure of leader tape engaging part which can engage an end part of a leader tape (the second tape leader) to a tape end hooking part in a tape cartridge without requiring a tab projected in the side of the leader tape.
U.S. Pat. No. 5,857,634, entitled: xe2x80x9cTake-up Reel Lockxe2x80x9d to Hertrich discloses a locking system for preventing a take-up reel of a tape drive from rotating when a tape cartridge is not inserted to the drive.
On the other hand, an example of the tape cartridge installed in the digital linear tape drive is disclosed in Japanese Unexamined Patent Publication Tokkai No. 2000-149491 (JP 2000-149491 A).
In addition, U.S. Pat. No. 6,241,171, entitled: xe2x80x9cLeaderless Tape Drivexe2x80x9d to Gaboury discloses a tape drive wherein a tape leader from a tape cartridge is urged through a tape path, into a take-up reel, and secured therein without the use of a bucking mechanism or a take-up leader.
In addition, the tape drive further comprises a tape head actuator assembly which is located between a take-up spool and a tape cartridge on a tape path defined by a plurality of rollers. During operation, a magnetic tape flows forward and backward between the take-up spool and the tape cartridge and is closely adjacent to the tape head actuator assembly while the magnetic tape flows on the defined tape path. An example of such as a tape head actuator assembly is disclosed in the above-mentioned U.S. Pat. No. 5,793,574.
Now, as is disclosed in the above-mentioned WO 86/07471, the first tape leader is coupled to the take-up reel while the second tape leader is connected to the tape on the supply reel contained in the tape cartridge. In addition, the tape leader is also called a xe2x80x9cleader tape.xe2x80x9d After the tape cartridge is inserted in the slot of the tape drive and then the tape cartridge (the supply reel) is engaged with the supply reel motor, the first reader tape and the second reader tape are coupled to each other by using the joining mechanism as disclosed in the above-mentioned WO 86/07295. As illustrated in the drawing of the above-mentioned WO 86/07471, a coupled or joined portion between the first leader tape and the second leader tape has a shape projecting from a surface of the leader tapes up and down. Thereafter, a xe2x80x9ctape-loadingxe2x80x9d for pulling the magnetic tape out of the tape cartridge (the supply reel) into the tape-up reel is carried out. In addition, after information exchange between the magnetic tape and the magnetic head in the magnetic head actuator assembly is completed, a xe2x80x9ctape unloadingxe2x80x9d for rewinding the magnetic tape from the take-up reel in the tape cartridge (the supply reel) is carried out.
As described above, inasmuch as the above-mentioned coupled portion has the shape projecting from the surface of the tapes up and down, on tape loading and on tape unloading, it is necessary to protect the magnetic head so that the above-mentioned coupled portion is not in contact with the magnetic head in the magnetic head actuator assembly. Such a protection mechanism is called a xe2x80x9chead protection mechanism.xe2x80x9d That is, by driving the protection mechanism except for a recording/reproducing mode in the tape drive, it is necessary to protect the magnetic head so that the above-mentioned coupled portion is not in contact with the magnetic head. On the other hand, on the recording/reproducing mode in the tape drive, by releasing the driving of the head protection mechanism, the tape drive operates so as to allow the magnetic tape to be in contact with the magnetic head. In other words, when the leader tapes (both of the first leader tape and the second leader tape) pass in the vicinity of the magnetic head actuator assembly, it is necessary to protect the magnetic head by driving the head protection mechanism so that the above-mentioned coupled portion is not in contact with the magnetic head.
In the manner which will later be described in conjunction with FIGS. 1 through 7, in a conventional head protection mechanism, it is necessary to lower the magnetic head from a normal used recording/reproducing position. As a result, an excessive space is required below the magnetic head. This prevents the tape drive from thinning. In addition, inasmuch as a driving force (a driving source) for the head protection mechanism is obtained by a stepping motor, the conventional head protection mechanism cannot have a sufficient axle ratio and is disadvantageous in that it is difficult to withstand a heavy lead.
It is therefore an object of the present invention to provide a head protection mechanism which is capable of thinning a tape drive.
It is another object of the present invention to provide a head protection mechanism of the type described, which is capable of withstanding a heavy lead.
On describing the gist of an aspect of this invention, it is possible to be understood that a head protection mechanism is for use in a tape drive. The tape drive comprises a chassis, a take-up reel rotatably mounted on a main surface of the chassis, a take-up reel motor mounted on a back surface of the chassis for rotatably driving the take-up reel, a slot disposed on the main surface of the chassis for inserting a tape cartridge containing a supply reel, a supply reel motor mounted on the back surface of the chassis at a position opposed to said slot for rotatably driving the supply reel in the tape cartridge, and a loading mechanism for engaging the supply reel with the supply reel motor after the tape cartridge is inserted in the slot. The loading mechanism includes a loading motor disposed on the back surface of the chassis and a ring cam operatively driven by the loading motor. The ring cam has a cam face. The ring cam is coaxial to a rotation axis of the supply reel motor. The ring cam is disposed between the back surface of the chassis and the supply reel motor. The tape drive further comprises an actuator assembly liftably mounted on the main surface of the chassis. The actuator assembly includes a magnetic head for carrying out information exchange between the magnetic head and a magnetic tape pulled from the supply reel to the take-up reel. The head protection mechanism is for protecting the magnetic head so that a coupled portion between a first reader tape of the take-up reel and a second reader tape of the supply reel is not in contact with the magnetic head on tape loading and on tape unloading. The head protection mechanism comprises a protection arm rotatably mounted on the main surface of the chassis close to the actuator assembly so as to cover the magnetic head. The protection arm has a tape passing groove through which the magnetic tape, the first and the second reader tapes pass. The protection arm includes an arm portion. Rotatably mounted on the back surface of the chassis, a protection lever has one end which is close to the ring cam and which is engageably disposed to the cam face. The protection lever has another end coupled to a tip of the arm portion in the protection arm via a hole bored in the chassis. Urging means always urges the protection arm nearer to the actuator assembly. When the tape drive is put into a recording/reproducing mode, the head protection mechanism acts to project the magnetic head into the tape passing groove so as to be in contact with the magnetic tape by positioning the one end of the protection lever at a position where the one end of the protection lever is not engaged with the cam face of the ring cam and by putting the protection arm close to the actuator assembly due to an urging force of the urging means. When the tape drive is not put into the recording/reproducing mode, the head protection mechanism acts to put back the magnetic head from the tape passing groove by engaging the one end of the protection lever with the cam face of the ring cam caused by rotatably driving of the ring cam using said loading motor and by separating the protection arm from the actuator assembly caused by rotatably moving of the protection lever in opposition to the urging force of the urging means. The urging means may comprise a spring has an end connected to the protection lever and another end connected to the chassis.